Material bending apparatus



May 24, 1960 R. L. PETERSON MATERIAL BENDING APPARATUS 3 Sheets-Sheet 1Filed Feb. 8, 1957 INVENTOR. 'fiobarzlfejaraviz,

@ u, M,M r

May 24, 1960 .R. L. PETERSON 2,937,689

MATERIAL BENDING APPARATUS Filed Feb. 8. 195'! 3 Sheets-Sheet 2 IN VENTOR.

L Ll Z MAM/7% May 24, 1960 R. L. PETERSON 8 MATERIAL BENDING APPARATUSFiled Feb. 8, 1957 3 Sheets-Sheet 3 lullll \l lNVENT dR: fiberziPzie/w 4w i W United State P t MATERIAL BENDING APPARATUS Robert Peterson,Elgin, Ill., assignor to Uniflex Englneermg, Inc., Elgin, 111., acorporation of Illinois Filed Feb. 8, 1957, Ser. No. 638,963

8 Claims. (Cl. 154-1) The invention relates to material bendingapparatus and has reference more particularly to apparatus for bendingsheet material such as thermoplastic materials over rounded edges of thetype provided by backing members and the like and wherein the arcuatecontour of the bend may vary in radii over a considerable range.

Objects of the invention are to provide a bending machine of novel andimproved construction which can bend or roll the terminal edges of sheetmaterial over arcuate surfaces such as may be provided by the backingmembers to which the material is simultaneously and adhesively secured,which will perform such bending functions by rolling the sheet materialin place in a single and continuous operation so that pre-forming of thesheet material is eliminated, and a machine which is designed tocompensate for varying thicknesses of laminatingstock by a movablerolling device. A simple adjustment permits larger radii to be rolled tothe same ratio and the time for accomplishing such a change is held to amini-' mum. Another object of the invention is to provide a bendingmachine as described which will incorporate heating means forpre-heating plastics and similar sheet material to facilitate thebending of the same. However, the utility of the present device is notnecessarily limited to the thermal-change type material but the saiddevice will roll and form or laminate sheet metal and other coveringmaterial over formed core stock.

A still further object is to provide a bending machine which willcomprise a self-contained production unit having scientifically designedfeatures which will permit its use -in ordinary normal production areas,and a machine as described which will be rugged in construction andwhich will conform to all engineering requirements to thus permit dayafter day repetitive use.

With these and various other objects in view, the invention may consistof certain novel features of construction and operation, aswill be morefully described and particularly pointed out in the specification,drawings and claims appended hereto.

In the drawings which illustrate an embodiment'of the device, andwherein like reference characters are used to designate like parts j IFigure l is a front elevational view illustrating the improved materialbending machine of the invention;

Figure 2 is asectional view taken transversely of the machine of Figure1 substantially on line 2-2 thereof;

Figure 3 is a fragmentary sectional view similar to Figure 2 but showingelements thereof in the position just prior to performing a bendingoperation; and

Figure 4 is a fragmentary, transverse, sectional view similar to Figure3 but showing the elements of the machine in the position they assume atthe completion of a bending operation.

Referring more particularly to the drawings, the apparatus selected forillustrating the invention consists of heavy supporting structureincluding the table having the legs 11 and which table provides a flattop-surface 12 on which is supported most of the bending elements of"weight for the bendinginstrumentalities and said flat top surface =12has suitably secured thereto the eye beams 13, 14 and 15, the formerproviding a support for the work-supporting member 16, and the eye beam15 having the pivot supports 17 secured thereto for pivotallymount-j ingthe arms 18. The arms 13 are actuated by power cylinders 20 which aresupplied with fluidunder pres-' sure, either air or liquid, and by meansof the piston rods 21 the said power cylinders are connectedrespectively at 19 to the arms 18. The hold-down bar 22 extends for thelength of the machine, as is evident from an inspection of Figure l, andsaid bar is fixedly secured to the arms 18 at their ends opposite thepivots 17. It will be understood that there is an arm 18 and a powercylinder 20 at each end of the machine, all as shown in Figure 1, andthus the hold-down .bar '22 is elevated and lowered by actuation of thepower cylinders 20. The baffle plate 23 is secured at 24 to thehold-down bar 22 and said baflle plate also extends for the length ofthe machine and has the function'of holding heat within the apparatus bypreventing cross currents of outside cool air.

For illustrating the mode of operation of the apparatus, a sheet ofplastic material 25 has been placed on the backing member 26, which isin turn supported on the work-supporting member v16, and an adhesive ofthe contact type was used for securing-the plastic sheet 25 to thebacking member 26. Following this operation the hold-down bar 22 islowered onto the plastic sheetto maintain the parts in place, withtheedge 27 of the sheet extending some distance outwardly beyond theworksupporting member so as to overhang the formed edge 28 of thebacking member. To prevent any scarring or damage to the top surface ofthe plastic sheet theholddown bar 22 may be provided with the soft'rubber pad 30.

The first step in the bending operation is to heat the overhanging edge27 of the thermoplastic sheet to soften the same whereby to facilitatethe bending of the sheet and this is; accomplished by'the heater 32which is. so-

cured at 33 to the supporting arm 34. 'Said arm is moved v to and froman operative position by the powercyhnder 35, having the piston rod 36,so that a pressure fluid admitted to the right hand end of the cylinderwill force the finger is so located as to receive the tip edge of theplastic sheet in order to support'the same during theheating operation.The operative position of the heater-is shown in Figure2. To retract theheater, pressure fluid is admitted to the left hand end of cylinder 35and the piston of said cylinder, piston rod 36, supporting arm' 34, andheater 32 are movedto an inoperative location, as best illustratedinFigures 3 and 4. r

This retraction movement of the heater 'into'its position of rest leavesthe projecting edge 27 of the'plastic 'sheet unsupported and accordinglysaid edge is nowincondition for bending, which is performed by a pivotedroll bar, as illustrated inFigures 3 and 4. However, it is firstnecessary to apply pressure to the plastic sheetat a point adjacenttheformed edge .28 of the backing member and this step in the method isaccomplished by a presser foot such as indicated by numeral 38. Saidfoot is generally in theform of a channel beam and:

Pivotedi arms 40 are employed for pivotally supporting Patented May 24,1960 the presser foot 38 and said arms are located at spaced intervalslengthwise of the machine, having pivotal securement as at 41 to theframe members 42, which rest on the flat top surface 12 of the table 10,being suitably secured thereto, and having an outwardly curved upper endso as to extend partly over said table.

The frame members 42 are joined at their top ends by the facing plate 43which extends for the length of the machine, thereby providing a supportfor suspending one end of each of the power cylinders 44. Each saidpower cylinder 44 is pivotally suspended from the facing plate 43 bymeans of the bifurcated pivot support 45 and stem 46. A piston rod 47extends from the opposite end of each power cylinder 44 and each pistonrod is pivotally secured as at 48 to the presser foot 38. Accordingly,the presser foot is raised or lowered through actuation of the powercylinders 44, which are connected so as to operate in unison. However,in order to make room for the heater 32 it will be seen that the presserfoot must be located in an elevated position and the operation oflowering the foot onto the plastic sheet can not be accomplished untilafter the heater has been retracted.

The arms 40 are grouped in pairs with respect to each of the powercylinders 44 and the arms of each pair are spaced sufiiciently toaccommodate between them a power cylinder 50 having pivotal connectionto said arms by means of the stud 51. The piston rod 52 of powercylinders 50 is pivotally secured at 53 to the hinge plate 54, the saidplate having a hinged connection at 55 with the presser foot 38. Theroll bar 56 has fixed securement to the underside of hinge plate 54 andsaid roll bar, in accordance with the invention, extends for the lengthof the machine. On the operating side of the roll bar there is provideda pad 57 which provides a relatively soft surface for contact with edge27 of the plastic sheet in bending and rolling the same around theformed edge 28. When the supporting arms 40 are lowered to bring thepresser foot 38 into contact with the plastic sheet, it will be observedthat the power cylinders 50 remain inoperative and thus the roll bar 56remains retracted during this operation. However, after the plasticsheet has been engaged by the presser foot the next operation of thepresent bending machine is to cause pivotal movement of the roll bar 56on its pivot point 55 and as a result thereof the edge 27 of the sheetis bent around the formed edge 28. Due to the adhesive previouslyapplied to the parts, the bent portion of the plastic sheet is caused tofirmly adhere to said formed edge. To efiect operating movement of theroll bar, a pressure fluid is supplied to the upper end of the powercylinders 50 and said cylinders are connected so that they operate inunison, with the result that the roll bar is moved from its retractedposition of Figure 3 to its operative position of Figure 4. It isdesirable to hold the roll bar 56 in its operative position of Figure 4for a short interval of time to assure adequate pressure on the edge 27for effecting its securement to the backing member.

The roll bar is retracted by admitting pressure fluid to the lower endof the cylinders 50, allowing the fluid to exhaust from the upper end.It will be observed that the roll bar is pivotally secured to thepresser foot and has pivotal movement with respect to said foot. It willalso be seen that the power cylinders 50 are carried by the supportingarms 40 so that a simple and compact arrangement of elements isaccordingly provided for performing two of the important functions inthe bending of a sheet, namely, first, that of holding the sheet firmlyin place on its backing member and at a location adjacent the formededge of the backing member, and secondly, that of bending the edge ofthe sheet over the bgcking member by applying rolling pressure to said ege.

With the retraction of the roll bar 56 the operation of bending the edgeof the plastic sheet is completed and the sheet can now be released byrelease of the presser foot 38 and release of the hold-down bar 22.Fluid pressure is applied to the lower ends of the cylinders 44 torelease the presser foot and simultaneously therewith fluid is releasedfrom the top end of the cylinders. Power cylinders 20 are similarlyactuated so that both elements, namely, the presser foot and thehold-down bar, are elevated, thereby releasing the workpiece Z5, 26,which can now be removed from the work supporting member 16. Anotherunfinished workpiece can be placed thereon for similar bendingprocedures and these can be accomplished by repeating thecycle ofoperations of the machine.

The bending apparatus as described is partly enclosed by means of a backwall such as 60 and end walls 61. Both walls may be formed of thin metalor other suitable material and the enclosure thus formed functions incombination with the bafile plate 23 to prevent infiltration of cool airsuch as might interfere with the heating of the plastic sheet.

The invention is not to be limited to or by details of construction ofthe particular embodiment thereof illustrated by the drawings, asvarious other forms of the device will of course be apparent to thoseskilled in the art without departing from the spirit of the invention orthe scope of the claims.

What is claimed is:

1. In material bending apparatus, in combination, supporting framestructure providing a work supporting member, a hold-down bar forholding a workpiece on the work supporting member, supporting arms forthe hold-down bar having pivotal connection with the frame structure,power means connecting with the arms for actuating the hold-down bar toand from an operative and a released position, a presser foot,supporting arms for the presser foot also having pivotal connection withthe frame structure, other power means for actuating the presser foot toand from an operative and a released position, a roll bar in spacedrelation with the presser foot but having pivotal connection with thepresser foot, and additional power means in associated relation with thesupporting arms for the presser foot for actuating the roll bar.

2. Material bending apparatus as defined by claim 1, additionallyincluding a heater and power means for reciprocating the heater in aplane substantially parallel to but above the plane of the workpiece andto and from an operative position approximately over the workpiece.

3. In material bending apparatus, in combination, supporting framestructure providing a work supporting member, a hold-down bar forholding a workpiece on the work supporting member, supporting arms forthe hold-down bar having pivotal connection with the frame structure,power means connecting with the arms for actuating the hold-down bar toand from an operative and a released position, a presser foot,supporting arms for the presser foot also having pivotal connection withtheframe structure, and constructed and arranged to permit the presserfoot to move to and from the workpiece, -other power means for actuatingthe presser foot, a roll bar in spaced relation with the pressure foot,means pivotally connecting the roll bar to the presser foot, andadditional power means for actuating the roll bar. said additional powermeans being supported by the sup porting arms for the presser foot.

4. Material bending apparatus, as defined by claim 3, additionallyincluding a heater and power means for reciprocating the heater in aplane substantially parallel to but above the plane of the workpiece andto and from an operative position approximately over the workpiece.

, 5. In material bending apparatus, in combination, frame structureproviding a work supporting member for a workpiece including a backingmember and a surfacing sheet adapted to be adhesively secured theretohold-down bar for holding the workpiece in assembled relation on thesupporting member, supporting arms for the hold-down bar having pivotalconnection with the frame structure, power cylinders connecting with thearms for actuating the hold-down bar to and from an operative andreleased position, a presser foot for contacting the surfacing sheetadjacent a projecting edge, supporting arms for the presser foot andalso having pivotal connection with the frame structure, other powercylinders for actuating the presser foot to and from a contactingrelation with the surfacing sheet, a roll bar pivotally connected inspaced relation to the presser foot, said roll bar having movement whenthe presser foot is in contact with the surfacing sheet for bending theprojecting edge of the sheet over a formed edge provided by the backingmember, and additional power cylinders in associated relation with thesupporting arms for the presser foot for actuating the roll bar.

6. Material bending apparatus as defined by claim 5, additionallyincluding a heater for heating the projecting edge of the surfacingsheet, and a fourth set of power cylinders for reciprocating the heaterin a plane approximately parallel to but above the plane of theworkpiece, said heater having an operative position over the projectingedge of the sheet only when the presser foot is in an elevated releasedposition.

7. In material bending apparatus, in combination, frame structureproviding a work supporting member for a workpiece including a backingmember and a surfacing sheet adapted to be adhesively secured thereto, ahold-down bar for holding the workpiece in assembled relation on thesupporting member, supporting arms for the hold-down bar having pivotalconnection with the frame structure, power cylinders connecting with thearms for actuating the hold-down bar to and from an operative andreleased position, a presser foot for contacting the surfacing sheetadjacent a projecting edge, supporting arms for the presser foot, saidsupporting arms also having pivotal connection with the frame structure,and constructed and arranged to permit the presser foot to move to andfrom the workpiece, other power cylinders pivotally suspended from theframe structure for actuating the presser foot, 2. roll bar in spacedrelation to the presser foot, means pivotally connecting the roll bar tothe presser foot, said roll bar having movement when the presser foot isin contact with the surfacing sheet for bending the projecting edge ofthe sheet over a formed edge provided by the backing member, andadditional power cylinders for actuating the roll bar, said additionalpower cylinders being fixed to and pivotally supported from the frame bythe supporting arms for the presser foot.

8. In material bending apparatus, in combination, frame structureproviding a work supporting member for a workpiece including a backingmember and a surfacing sheet adapted to be adhesively secured thereto, ahold-down bar extending longitudinally of the frame structure forholding the workpiece in assembled relation on the supporting member,supporting arms for the hold-down bar having pivotal connection with theframe structure, power means connecting with the arms for actuating thehold-down bar to and from operative and released positions, a presserfoot for contacting the surfacing sheet adjacent a projecting edgethereof and between said edge and the hold-down bar, supporting arms forthe presser foot, said supporting arms also having pivotal connectionwith the frame structure and providing for movement of the presser footto and from the workpiece, other power means pivotally suspended fromthe frame structure for actuating the presser foot, a heater supportedfor movement in a substantially horizontal plane above the workpiece forheating the said projecting edge when positioned over the same, asupporting member for releasable contact with the said projecting edgefor supporting said edge during the heating operation, a roll barpivotally connected to the presser foot, and means for actuating theroll bar when the presser foot is in contact with the surfacing sheetfor bending the projecting edge of the sheet over a formed edge providedby the backing member.

References Cited in the file of this patent UNITED STATES PATENTS368,475 Johnson Aug. 16, 1887 746,090 Johnson Dec. 8, 1903 2,175,679Beatty Oct. 10, 1939 2,648,370 Beach Aug. 11, 1953 2,739,637 Tyler Mar.27, 1956

